Glass collimation lens for 532nm green laser modules (focal length: 25mm) They are flat convex glass lenses for 532nm green lasers! Especially for 25mm in-focal length beam collimation! This laser lens is a high permeability optical component used for as industrial test, Lab, DIY. Please keep the lens clean to make the laser beam clear and bright. Before carrying on some laser DIY activities, please read about the technical information first and protect your eyes before laser ray. Be sure the operator has experience in optics DIY or test.